But none have caused as big a firestorm as the intelligence leaks that led to the resignation of national security adviser Michael Flynn.

Fortune reported that Flynn's resignation will not put an end to the questions regarding the alleged connections between Russia and Trump's inner circle. But as usual, Trump used Twitter as his bully pulpit to make a series of accusations while wondering which agency is leaking information. He wrote, "Information is being illegally given to the failing @nytimes & @washingtonpost by the intelligence community (NSA and FBI?). Just like Russia."

Information is being illegally given to the failing @nytimes &amp; @washingtonpost by the intelligence community (NSA and FBI?).Just like Russia

He later tweeted, "The real scandal here is that classified information is illegally given out by 'intelligence' like candy. Very un-American!"

The real scandal here is that classified information is illegally given out by "intelligence" like candy. Very un-American!

But who is "intelligence," anyway, and how does each agency differ from the other? Here is a breakdown:

CIA

The Central Intelligence Agency is the country's chief gatherer of intelligence overseas. Officially formed in 1947 under the National Security Act, it is currently led by Mike Pompeo. According to the agency's website, the CIA's mission is to "collect, analyze, evaluate and disseminate foreign intelligence to assist the president and senior U.S. government policymakers in making decisions relating to national security." Once a foreign threat is identified, the CIA conducts an intelligence study and then it looks for ways to collect information about said problem.

FBI

The Federal Bureau of Investigation was founded on July 26, 1908, and it is currently headed by James Comey. It mostly focuses on domestic cases. According to the FBI's website, its mission is to investigate specific crimes assigned to them and provide law enforcement agencies with fingerprint identification, laboratory examinations, training and other services. While the FBI also gathers and analyzes intelligence, it works directly with the Department of Justice, whereas the CIA and other intelligence agencies deal with the State Department or the Department of Defense.

The FBI was a key investigation agency in domestic terror cases such as the 1995 bombing of a federal building in Oklahoma City and the Sept. 11 attacks. In the 1950s and 1960s, while still led by longtime director J. Edgar Hoover, the agency was behind the controversial Counterintelligence Program — also known as COINTELPRO — which targeted suspected communists, Martin Luther King Jr. and participants in the Civil Rights Movement.

NSA

Founded on Nov. 4, 1952, the National Security Agency is responsible for collecting, monitoring, and processing information and data for counterintelligence and foreign intelligence actions, also known as the signals intelligence— or SIGNIT. It is also in charge of cryptology, or as its website describes it, "the art and science of making and breaking codes." Adm. Michael S. Rogers has served as NSA director since 2014.

The Washington Postreported that the NSA's phone data collection program has disrupted at least 42 cases of potential terror plots in the U.S. and abroad. However, organizations such as Electronic Frontier Foundation have sued the NSA for conducting dragnet surveillance on U.S. citizens.

DIA

According to its website, the Defense Intelligence Agency provides military intelligence to soldiers and fighters in the field, defense policymakers, officials in the Department of Defense and the intelligence community. The DIA has become the chief source of foreign intelligence for all combat and combat-related missions undertaken by the U.S. The agency was founded on Oct. 1, 1961 under the recommendations of then Secretary of Defense Robert McNamara and is currently directed by Lt. Gen. Vincent R. Stewart.

The DIA provided intelligence that led to the takeover of the Son Tay prison camp in Vietnam to rescue U.S. prisoners of war in 1970, as well as for the 1983 U.S. invasion of Grenada and the 1993 Operation Restore Hope that sought to capture Somali warlords.